Over 400 hypertension-related traits have been measured on 923 individuals in five large families. These families were originally ascertained in the 1970's through single probands with essential hypertension by Dr. Roger Siervogel of Wright State University. DNA was extracted from 25-year-old stored samples and genotyping for nearly 400 polymorphic genetic markers was done by the Center for Inherited Disease Research. However, because of problems with DNA extraction and limited amplification, polymorphisms could be determined for only about 250 individuals. During the past year, a contract was established with Dr. Siervogel to 1) develop an IRB protocol to recontact these families for a 30 year follow-up, 2 to redraw blood from missing individuals and 3) to extract and store DNA from these samples. Efforts are now underway to recontact these families, obtain blood and retype missing individuals to complete the study. Model-independent linkage analysis will be done to determine if genetic components responsible for variation in each of the hypertension-related traits can be identified and localized in the human genome.